“In the process, Meng discovered the chemical reaction generated hydrogen peroxide
as a byproduct of oxidation,” says Bruce Lee, associate professor of biomedical engineering and Meng’s PhD advisor at Michigan Technological University. “She started thinking,
what if we could use the hydrogen peroxide?”

The answer is yes, and the technology that makes this portable, healing disinfectant
possible is the subject of a new paper published in Acta Biomaterialia (DOI: 10.1016/j.actbio.2018.10.037). The work brought together an interdisciplinary team of engineers to explore not
only the tech development but also the material’s physical and biological properties.

Just like Jello

After Meng first observed that her reactions created hydrogen peroxide, she started
considering the best form to put the byproduct in. She wanted lots of surface area
to power the chemical reaction and she wanted a way to reuse the material. So, the
team made a microgel.

“The gel is just like jello,” Lee says. “It’s a polymer network with a lot of water
in it. And just like jello, we start with a liquid and solidify it into a shape.”

Microgels are like tiny bubbles of jello. To the naked eye, the dry form is a nondescript
powder. Suspend it in a solution with neutral or a slightly alkaline pH, such as distilled
water or a saline solution like contact lens cleaner, and the hydrogen peroxide cycle
gets rolling. Left to its own devices, the micron-sized microgels generated between
one to five millimolars over four days. Once the microgel powder is dried again, the
material basically resets, sits safely contained in a small bag, and can be reused.
It’s like an on-demand bottle of disinfectant — without the bulky bottle and hazardous
storage issues.

The team tested their microgel powder against two bacterial strains and two viruses;
the hydrogen peroxide generated successfully reduced the strains’ ability to infect
by at least 99.9 percent.

Antimicrobial and Antiviral

The inspiration for that iconic brown bottle in the medicine cabinet didn’t start
in a lab; the body naturally produces hydrogen peroxide to help heal cuts and the
substance has been widely used medicinally to kill off bacteria and even viruses.
Because the microgel powder continues to create and release hydrogen peroxide, its
potency remains high, especially compared to the old-school cotton ball technique.

The team studied the microgel’s effects on two common bacterial strains and two structurally
different viruses. That includes the thin-walled and gram-positive Staphylococcus epidermidis, as well as the more impenetrable and gram-negative Escherichia coli (E. coli). They also looked at the extremely resistant non-enveloped porcine parovirus
(PPV) and easier to inactivate enveloped bovine viral diarrhea virus (BVDV). Because
of the hard protein casing around PPV, which makes it and other non-enveloped viruses
more resistant to biocides, the team was pleasantly surprised to see that the microgel
still reduced the virus’ ability to infect cells by 99.9 percent. (In technical terms,
that’s a three log reduction value of infectivity.) With BVDV, they observed a 99.999
percent reduction in infectivity.

From Camping to Battlefields

The possibilities are almost endless. Wherever a small bag can go, so could this technology.
Whether it’s backcountry travel, space stations, remote clinics or war zones, a little
bit of healing to prevent infection can go a long way. While Lee and his team say
the tech is not quite ready for Amazon Prime, they are hopeful that the work shows
promise for a variety of applications, perhaps even with antibiotic resistance.

“We haven’t tested any antibiotic-resistant bacterial strains yet, but the more we
can get away from using antibiotics in the first place, the better,” Lee says. “There’s
still a lot of work to be done. We want to demonstrate under what conditions it promotes
healing and how a cell responds to it. Hydrogen peroxide at high concentrations can
also kill cells, so we need to have a balance that changes for different cell types.”

Lee recently received funding from the Department of Defense Office of the Assistant
Secretary of Defense for Health through the Defense Medical Research and Development
Program to continue this line of research. What started with a sticky protein’s waste
will be refined into a lightweight, portable and recyclable microgel powder with enough
oomph to kick even the most stubborn bacterial and viral infections.

Bruce Lee is a biomedical engineer and has studied numerous applications of mussel-derived
amino acids.

Michigan Technological University is a public research university, home to more than
7,000 students from 54 countries. Founded in 1885, the University offers more than
120 undergraduate and graduate degree programs in science and technology, engineering,
forestry, business and economics, health professions, humanities, mathematics, and
social sciences. Our campus in Michigan’s Upper Peninsula overlooks the Keweenaw Waterway
and is just a few miles from Lake Superior.

Grants and Funding

National Institutes of Health R15GM104846, the Office of Naval Research Young Investigator
Award N00014-16-1-2463, the Office of the Assistant Secretary of Defense for Health
through the Defense Medical Research and Development Program under Award number W81XWH1810610,
the Portage Health Foundation, the National Science Foundation DMR 1410192 and CBET
1451959, and the Mack Chair in Bioengineering.

Hao Meng was supported in part by the Doctoral Finishing Fellowship provided by the
Graduate School at Michigan Technological University. The authors acknowledge the
Applied Chemical and Morphological Analysis Laboratory at Michigan Tech for use of the instruments and staff assistance.

About the Author

Allison Mills

A through and through geek, Allison writes university research stories. She studied
geoscience as an undergrad at Northland College before getting a master's in environmental
science and natural resource journalism at the University of Montana. She moonlights
as a dance instructor, radio fiend, and occasional rock licker.